JPS59115502A - Thick film resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (c) Technical Field of the Invention The present invention relates to thick film resistors, and particularly relates to the shape of a highly reliable resistor pattern.

(bl) Prior Art and Problems As is well known, in thick film hybrid integrated circuits (ICs), resistors and conductors are printed on an insulating substrate (ceramic substrate). Conductors for wiring are made of, for example, silver palladium (^gP).
d) type material, the resistor is made of, for example, ruthenium oxide (R
It is a material that is a mixture of uO2) and an insulator, and is created by dissolving them in a solvent, printing them to a thickness of several μm, and firing them. However, since the printing thickness varies and is not constant, it is difficult to form the resistor as it is to have an accurate resistance value. Therefore, it has a low resistance value in advance (
In other words, after forming a resistor (having a wide resistive film surface), the resistance value is adjusted by removing the resistive film surface linearly by trimming (for example, laser trimming or sandblasting).

Figure 1 shows a plan view of the resistor after such trimming, where l is the resistance film, 2 is the conductor film, and 3 is the trimming line.The width of the resistance film is about 1 fl square, and the resistance value is several ohms
~ several Ω (the resistance value is set to the desired value by changing the mixing ratio of the insulators). As for trimming, laser trimming is often used recently, and a trimming line is formed by scanning with a laser beam having a beam diameter of several tens of micrometers. Since the scanning speed is controlled by a step motor, the trimming length error is 20 μm or less, which is extremely accurate.

However, in the trimming process, the ceramic substrate is heated to a high temperature by laser scanning and cooled down rapidly, causing microcranks in the resistive film. Furthermore, when a high surge current flows during operation, this micro-cracking causes damage to the resistor and a corresponding change in resistance value, which can vary by more than 10%.

(cl) Purpose of the Invention The present invention proposes a thick film resistor that eliminates the occurrence of such microcracks.

(dl) Structure of the Invention The object can be achieved by a thick film resistor in which a plurality of mesh-shaped windows are provided on the resistive film surface.

(e) Examples of the invention An embodiment will be described in detail below with reference to one drawing.

FIG. 2 shows a plan view of a resistor according to the present invention,
1 is a resistive film, 2 is a conductive film, and is similar to that shown in FIG. 1, but a large number of windows 11 (windows in the raw material of the ceramic substrate without the resistive film coated thereon) are provided on the surface of the resistive film 1. In the example shown in FIG. 2, 40 such windows 11 are formed in a mesh shape over 60% of the entire surface of the resistive film.

Thus, a trimming line 3 is formed in the trimming process, and this trimming line has a key shape ("shape") as in the conventional method.
However, it is preferable to draw a large number of trimming lines in a straight line from window to window as shown in Fig. If you draw a large number of trimming lines in this way, the longest line will have a large effect on the resistance value, and the shorter the lines, the smaller the effect on the resistance value, so you can mix these lines and finely adjust the resistance value. can.

In this way, the crop is scanned from window to window,
By making the end point inside the window, the micro-crank becomes extremely small, and the accompanying damage to the resistor and change in resistance value are prevented. Conventionally, microcracks were most likely to occur and grow at the bends and ends of the trimming line, but with this method, the corners and ends can be placed inside the window, completely eliminating this drawback. removed.

The appropriate size of this window is at least twice the beam diameter of the laser beam, and is suitably 100 to 200 μm square. Alternatively, if the above-mentioned trimming method is adopted even if the size is several hundred μm square, the resistance value can be adjusted with the same accuracy as in the conventional method. However, in terms of accuracy, a small area is more desirable, and in terms of fabrication, it is easier to create a window with a large area. In addition, since the resistance value of such a resistor is affected by the gap width in the direction of the conductor and the number thereof, it is necessary to take these into consideration when designing.

(fl) Effects of the Invention As is clear from the above description, according to the present invention, a thick film resistor whose resistance value does not change during operation is formed, which significantly contributes to higher reliability of hybrid ICs.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional trimmed thick film resistor, FIG. 2 is a plan view of a thick film resistor according to the present invention, and FIG. 3 is a plan view of a trimmed thick film resistor. In the figure, 1 is a resistive film, 2 is a conductive film, 3 is a trimming line, and 11 is a window. Fig. 1 5B, 4.14 Mr. Commissioner of the Japan Patent Office 1 (f'1's front face Showa! 7 +1' f, l'll'l' 222nd year! Shi J3, +ill it-') I(1'l,!: ) leap f# 1=74
'l'71 temporary f1 person 11 location Kamiyayo Prefecture Kawasaki 11 Kawarie; ilK llI・11 Kawari 015 sound location (522) Name Fujitsu Ltd.

Claims (1)

[Claims] A thick film resistor characterized in that a plurality of mesoche-shaped windows are provided on a resistive film surface.